Air driven rotary earth auger



June 3, 1958 E. B. LEAR 2,837,316

AIR DRIVEN ROTARY EARTH AUGER Filed Jan. 14. 1953 6 Sheets-Sheet 1 EARL B. LEAR June 3, i958 E. B. LEAR AIR DRIVEN ROTARY EARTH AUGER 6 Sheets-Sheet 2 Filed Jan. 14, 1953 IN V EN TOR.

EARL EAR BY y ATTORNEY June 3, 1958 E, B LEAR AIR DRIVEN ROTARY EARTH AUGER 6 Sheets-Sheet 3 Filed Jan. 14. 1953 VON INVENTOR.

EARL B. LEAR June 3, 1958 E. B. LEAR AIR DRIVER ROTARY EARTH AUGER June 3, 1958 E. B. LEAR 2,837,316

AIR DRIVEN ROTARY EARTH AUGER Filed Jan. 14. 1953 6 Sheets-Sheet 5 T l al f90l 193 126 fas J1 x25 5' lza 191 f2? 129 zzz INVENTOR.

EARL LEAR @WJ/am June 3, 1958 E. B. LEAR AIR DRIVEN'ROTARY EARTH AUGER Filed Jan. 14, 1953 6 Sheets-Sheet 6 mm QM NNN. wm.

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@Wwf/9M ATTORNEY United Stte rml AIR DRIVEN ROTARY EARTH AUGER Application January 14, 1953, Serial No. 331,270

8 Claims. (Cl. Z55- 47) This invention relates to an air driven rotary earth auger and more particularly to an earth auger adapted to be supported in a mine drift for the purpose of drilling blast holes therefrom.

Under the present day practice in mines, the large bodies of the ore are generally rst cut into along a horizontal plane to provide a mine drift or hole and semicircular steel sets are disposed along the hole and wood timbers are run lengthwise over and between the sets to provide protecting roof. In order that the great body of metal ore lying around the hole having the sets and timbered drifts will be deposited inthe hole for removal, blast holes are drilled into the ore body with rotary earth angers to distance of several feet from the mine drift. These blast holes are drilled in many directions and are filled with blasting powder. The blasting charge is set olf and large volumes of the ore are loosened and accumulated around the drift and timbers. This ore may thereby collect about and enter the sides of the hole under the wood timbers and will continue to enter as a scraper keeps dragging the ore through the hole and until the blasted volume of loose ore mass has been depleted. These operations may continue through the entire ore mass until the mine may be completely chambered.

It is accordingly an object of the present invention to provide a rotary earth auger which is operated by air pressure usually available in mines that will effectively and efciently prepare the blast holes from the wood timbered drifts and deep into the surrounding ore mass.

It is another object of the invention to provide the independently-controlled feed and auger motors Lin a single housing with a common air supply and control that are movable, together, as a unit along the guide shell support.

it is another object of the invention to provide an air driven rotary earth auger for drilling from a mine hole wherein the feed shaft is held stationary while the motor feed nut depending from the housing travels therealong, and the shaft has an overload clutch device at its end adapted to release when the travel of the unit housing has been interrupted either by the load on the auger or. by engagement of the auger chuck with a timber or ore body wall, and wherein the bulfer springs that take up the slack at the end of the forward and return travel of the unit are fashioned to be simply connected to the ends of the guide shell against displacement therefrom.

lt is another object of the invention to provide an. air driven rotary earth auger wherein one of the planetary gear spiders for the gear reduction of the auger motor will be mounted and supported between the drive pinion of the motor itself and the chuck spindle and wherein the chuck spindle provides the other planetary gear spider.

It is still another object of the invention to provide a double planetary gear reduction for an air driven rotary auger unit wherein the internal ring gear elements are Xed against rotation by the bolts that tix the gear case to the end of the valve and motor housing.

arent-YO 2,337,315 Patented .lime 3, 1953 It is still another object of the invention to provide an air driven rotary auger unit wherein air pressure resulting from leakage of air from the air motors within the unit is vented to the gear drive of the feed motor with the driving nut to force lubricant over gears and into the drive nut and onto the threaded feed shaft.

Other objects of the invention are to provide an air driven rotary earth auger for use in mines which is of simple construction, easy to assemble, light in weight, compact, durable, easy to install and set up within the mine shaft drift, easy to control and operate and efficient in operation.

For other objects and for a better understanding of the invention, reference may be had to the following detailed description taken in connection with the accompanying drawing, in which:

Figure l is a perspective view of the air driven earth auger of the present invention mounted within the mine` drift and being in position to drill a blast hole in the overhead ore mass;

Fig. 2 is a top plan view of the auger unit mounted on the guide shell, which has the centralizer mechanism on one end and the clutch on the opposite end with portions of the unit housing broken away to show the arrangement of the control valves;

Figs. 3a and 3b are enlarged longitudinal sectional views of the auger with one view being a continuation of the other but the respective views being on separate sheets, these views being taken generally on line 3-3 of Fig. 2;

Fig. 4 is a fragmentary, collective and perspective view of the parts of the overload clutch assembly for the feed shaft, certain of the elements being broken away and shown in section;

Fig. 5 is a transverse sectional View taken through the auger unit on line 5-5 of Fig. 3a, and including the auger motor;

Fig. 6 is a transverse sectional view taken through the reduction gear case and on line 6 6 of Fig. 3a;

Fig. 7 is a partial transverse sectional View taken of the driving gears extending between the feed motor and the threaded feed shaft, including the feed nut, the view being taken generally on line 7--7 of Fig. 3b;

Fig. 8 is an end elevational View of the auger and o-f the sliding cone mount to which the guide shell is clamped;

Fig. 9 is a transverse sectional view taken through the feed motor and its control valve and generally on line 99 of Fig. 3b.

Referring now particularly to Fig. l, there is shown a mine drift or hole 15 which has semi-circular heavy steel sets 16 spaced longitudinally through the drift and on which are supported wood timbers 17 that run between the steel sets to support any loosened ore mass. The sets are formed of sections with flanged ends connected together as shown at l by bolts 19. The wood timbers extend over the upper part of the sets and downwardly part way over the sides thereof. Beneath the wood timbers ore 20 can How into the mine drift or hole 1S. In order to maintain the flow of the ore, the ore body as indicated at 21 lying above the sets or at the sides thereof is drilled with blast'holes 22 and 23 with the air driven rotary auger of the present invention, indicated generally at 24 and having an auger element 25 that drills the holes. These blast holes are drilled into the mass 21 a distance of twenty-five or more feet by simply joining the drill auger elements together. The blast holes are lled with powder charges and when exploded, the ore mass 21 will be pulverized and flow onto the wood timbers 17 and downwardly over the same and beneath them and into the drift or hole 15. A scraper is used thereafter to Vpull the ore out of the mine drift or hole 15.

The rotary auger 24 is mounted upon a sliding cone device 26 extending laterally upon and secured by a saddle clamp 2'7 to a vertically-extending post support 28 that engages at its upper end with one of the steel' sets 16 with its top plate 29. The lower end of the post has a transverse member 31 in which jackscrews 32 and 33 are threaded. These jackscrews respectively have base plates 32 and 33' which are rested on a wood block 34 in the bottom of the mine drift The jackscrews are tightened to have the post 23 rigidly fixed between the bottom of the drift 15 and the set 16. The rotary auger has a long guide shell 36, that has a normally stationary feed screw 37 therein, Figs. 3a and 3b, a motor and valve housing 38 and a reduction gear case 39 from which extends auger chuck 4t) to which the drill auger is attached. A control valve handle 42 is accessible on the top of the valve housing 38 to control the operation of the auger motor. A valve control handle 43 will control the operation of the feed motor. The operator having his respective hands on these control valves may regulate the speed of drilling and the advancement or retraction of the auger into the ore mass 21. An air supply hose 44 delivers air to the valve housing 38.

On the upper end of the guide shell 36 is a centralizer mechanism 45 for supporting and guiding the drill auger during the starting of the same through the wood timbers and between the sets and into the ore mass, and which is releasable by the operator at any time by the separation of parts thereof or by the engagement of the end of the gear case therewith as the auger unit advances on the guide shell 36. On the lower end of the guide shell 36 is an overload release or clutch mechanism 46 which will permit the release of the normally stationary threaded shaft 37 upon the auger being unduly loaded or upon the gear case 39 engaging with the wood timbers and at the end of the thrust of the auger unit.

The guide shell 36 is best shown in section in Fig. 9 and includes a bottom or base portion 48, spaced side portions 49 and 50 in which are respectively cut guide slots 51 and 52. Between these side portions 49 and 50 is a longitudinal space S3 in which the threaded feed screw 37 is disposed. The feed screw 37 is supported at its upper end on a centralizer bracket S4, Fig. 3a, by its reduced end 55 that is journalled in sleeve bushing 56 on the bracket 54. The bracket 54 carries the auger centralizer mechanism 4S. Surrounding the centralizer end of the feed screw 37 is a front feed screw buer spring V 57. The spring 57 has reduced diameter portion 57 that surrounds the reduced end 55 of the screw and engages the end of the threads to retain it against displacement therealong.

The rear end of the feed screw 37 has a flange 58 and a splined portion 59 which is journalled in the overload release assembly 46. A rear feed screw buffer spring 60 surrounds the rear end of the feed screw and has an enlarged end 61 ahead of the fiange 58. This enlarged end 61 is held against shoulder 62 of feed screw support member 63 to prevent its displacement into the guide shell. A hole 63 allows dirt to leave the support member. The support 63 and a feed screw clutch housing 64 member are fixed to the end of `the guide shell 36 by stud bolts 64 and nuts 64". Within housing 64 is a clutch spring 65 that bears against a clutch cone 66 with a predetermined pressure to hold the cone within internally tapered clutch sleeve 67. This clutch sleeve 67 vis seated against the end of support 63 and tiange 58. The cone 66 is splined to the splined portion 59 of thefeed screw and is frictionally held against rotation by its frictional engagement with the clutch sleeve 67. A hole 69 facilitates the cutting of a slot 68 for key 68 in housing 64 and at the same time serves for the escape of dirt therefrom. The clutch sleeve 67 is xed against rotation to the clutch housing 64 by a key 68. In this manner the feed screw 37 is normally held against rotation within the guide shell 36.

In order to feed the drill unit 24 that includes the valve and motor housing 38, gear case 39, auger 25, a motor driven feed screw nut 70 is provided. This feed nut is journalled in a rear feed screw nut bushing 71 carried in a depending portion 72 of a rear cover plate 73 fixed to the open end of valve and motor housing 38 by screws 74. The rear end of the feed screw nut 70 projects through the end of the depending portion 7?. and contains a rear buffer spring washer or wear member 74 that will engage the rear buffer spring 60 as the unit 24 is retracted to its full extent. The forward end of the feed screw nut 70 is journalled in a front feed screw nut bushing 75 carried by a depending portion 76 of the housing 38 that mates with the depending portion 72 of the rear cover plate 73.

The feed screw nut 70 has gear teeth 77 with which a feed motor idler gear 78 meshes. This gear 78 has gear teeth 79 meshing with the gear teeth 77 of the feed screw nut 70 and front gear teeth 31 that mesh with feed motor pinion 82 of a feed motor unit indicated generally at 83. The idler gear 78 is journalled on spaced needle bearings 84 and 85 supported on a hollow idler gear stud 86 fixed to the rear cover plate 73 and projecting into a stud supporting portion 87 of a cylindrical spacing member 87 fitted in the housing 38. A grease fitting S8 is threaded into the stud 86 and is accessible through a hole 89 in the back cover. Grease or oil is thus injected into the stud 86 and will be dispensed through radial holes 90 thereof to idler gear bearings 84 and 85 and through radial holes 91 in idler gear 78 to front feed screw nut bushing 75 and to idler gear teeth and feed motor shaft pinion 82. Grease is delivered to rear bushing 71 through hole 92 in the depending portion 72 of the back cover 73. The bushing 71 has holes 92 for receiving the lubricant and the front bushing has a similar hole 93 whereby the feed nut will be continually lubricated.

The feed motor 83 is fitted tightly within a cylindrical recess 95 of the valve and motor housing 33, Figs. 3b and 9, and generally comprises a liner 94, an eccentricallyarranged rotor 96 having radially adjustable circumferentially spaced blades 97 and front and rear motor rotor end plates 98 and 99. The feed motor 83 is held in the cylindrical recess 95 against rotation by a dowel and vent pin 101 extending from vent hole 101 in housing 38 and has a reduced diameter portion 102 that projects through the rear end plate 99 and into a hole 103 of the cylindrical spacing member 87. This pin has a central opening that extends through its entire length and serves to allow accumulated air in the housing forwardly of the motor 83 to be vented to the rear of the motor where it is used to force the lubricant outwardly through the bearings and to the feed nut. A radial hole 103 leads from hole 103 in member 87.

The rear end plate 99 has a ball bearing assembly 105 that supports the pinion end of the rotor 96. The bearing assembly 105 is made secure to the plate 99 by a 4washer 106 and -a lock screw nut 107 threaded upon the pinion 82.

The feed motor end plate 98 carries a ball bearing assembly 108 that supports the forward end'of the rotor 96. A lock screw 109 fixed to the front end of the rotor g 96 secures the bearing assembly 108 against forward displacement therefrom. The rotor end plates 98 and 99 respectively have the respective sleeve bushings 110 and 111 inwardly of the respective bearing assemblies in which the rotor is journalled also, the end plates respectively have oil holes 98 and 99 to permit the iow of oil between the ball bearings and the interior of the feed motor. An oil fitting 100 is provided in the side of housing 38 to supply oil thereto, Fig. 3b.

The motor liner 94 is relieved at one side to provide an air space 113, VFig. 9, and has ports 114 to deliver air under pressure to the interior of the motor from an air passage 115 in the housing 38, Fig. 3b, whereby to irnpinge the blades 97 and caure clockwise rotation of the rotor 96 as viewed in Fig. 9. The liner 94 is `also relieved on the opposite side thereof to provide an air space 116 and has ports 117 to deliver air under pressure against the blades 97 and turn the motor shaft ina counter clockwise direction upon air being delivered through the pas sage 118. The air from the interior of the motor liner 94 is primarily exhausted through slots 119 in the bottom thereof and through holes 120 in the bottom of the valve and motor housing 38.

The valve and motor housing 38 has later-ally extending guide projections 121 yand 122, Fig. 9, that extend a substantial length throughout `the extent of the housing and are guided respectively in the guide recesses 51 and 52 of the guide shell 3.6, Figs. 5, 8 and 9. The auger unit 24 will accordingly be either .advanced or retracted on the guide shell 36 and along the feed screw 37.

In the forward part of the valve and motor housing 38 is an auger motor 124, Figs. 3a, 3b and 5, which comprises generally a rotor liner 125, that is tightly tted within a cylindrical opening 126, a rotor 127 eccentrically arranged within the liner 125 and having circumferentially spaced radially extending slots 128 in which are disposed radially adjustable blades 129. On the front and rear of the rotor liner 125 are respectively front and rear auger motor end plates 131 and 132. The rear end plate 132 has a bushing 134 and a ball bearing assembly 135 in which a reduced end 133 of the auger motor rotor 127 is journalled. The ball bearing assembly 135 is held in place and as well as the auger motor rotor 127 is held against forward displacement by an auger motor rotor bearing retainer screw 136 having a left hand thread portion 137. The rotor 127 is shouldered at 138 to engage the end of the bushing 134, Fig. 3b. The front end plate 131 has a small bushing 139 and a ball bearing assembly in which the motor rotor 127 is journalled, Fig. 3a.

The rotor 127 has an extension 141 to which a pinion gear 162 is splined by keys 143. The pinion gear 142 is held in place on the extension 141 by a washer 144 and a lock nut 141-5 titted in a recess in the end of the pinion 1452 and threaded upon the extension 141.

On the forward end of the pinion gear 142, a planetary .spider 146 is journalled by means of a needle bearing assembly 147. This spider has three circumferentiallyspaced studs 148 that support bearing assemblies 149 and planetary pinions 150. These planetary pinions 150 mesh with the pinion gear 162 to be driven thereby and react against internal gear 151 that is held in spaced relationship within the gear case 39 by a gear case spacer 152 ttted in the front end of the valve and motor housing 38 and against the motor end plate 131 of the auger motor 124. Accordingly, as the auger motor rotor 127 is turned, the gear 142 will drive the planetary pinions 15) which will react against the internal gear 151 to rotate the spider 146 at a reduced speed.

The spider 1116 has a reduced portion 153 with gear teeth 154 thereon. A chuck spindle 155 is journalled on this reduced portion 153 by means of a needle bearing assembly 156 which has a spider formation 157 with circumferentially spaced studs 158 disposed thereon. On the studs there are respectively journalled planetary pinions 159 by needle bearing assemblies 166 and meshing with an internal gear 162 against which the planetary pinions 159 will react to cause the rotation of the chuck spindle 155 at a further reduced speed. The internal gear 162 is held against shoulder 162' on gear case 39 by a cylindrical spacing member 161, Fig. 3a.

This chuck spindle 155 is journalled in a reduced end 163 of the gear case 39 by front -and rear ball bearing assemblies 1641 and 165 longitudinally spaced from each other. The chuck spindle 155 has a threaded portion 166 on which a chuck spindle nut 167 is tightened to hold shoulder 168 of the chuck spindle 15S against the rear 6 bearing assembly and the front bearing assembly 164 in its recess 169. The chuck spindle nut 167 is locked in place by set screws 171. A chuck spindle seal 172 is held over the end of the ball bearing assembly 164 by a gear case cap 173 secured to the reduced portion 163 of the gear case 39 by cap screws 174.

The auger chuck 40 has a reduced hexagonal drive .shank 1'75 that is tted into a hexagonal opening in the chuck spindle 155 and held in place therein by a chuck pin 177 so that a shoulder 178 is held fixed against the end of the chuck spindle 155. The chuck 40 has a quar- 'ter' octagonal opening 179 that receives corresponding shank 188 of drill auger 25.

The centralizer mechanism 45 is of the usual construction and has separable guide arms 182 and 183, Figs. 2 and 3a, that can be adjusted to open positions and away from the auger 25 .either by hand or upon their being engaged by the gear case .cap 173 during lits upward travel `with the auger 25. These separable guide arms are normally maintained in their operative position upon bracket 54 by biasing spring 184, a ring collar 185 and a split ring 186 tted into a recess on the end of a bracket trunnion 187. A threaded hole 188 is for the purpose of attaching a device used to compress collar 185 and spring 18d` in order to seat the split ring 186 in its recess.

The centralizer assembly includes pins 188' and 188" for holding the inner parts assembled upon bracket 54. The bracket 54 has a knockout opening 189 and 189" aligned with the pins 188' and 188".

The auger motor 124 is held within the valve and motor housing 38 against rotation by a pin 189 that enters front end plate 131, Fig. 5. Air under pressure from passage 19t) passes through ports 191 of the rotor liner 125 and will impinge the blades 129 to cause rotation of the auger rotor 127 in a clockwise direction, as viewed in Fig. 5, and this air will exhaust through side slits or ports 191 and 192 into a passage 193 and into and outwardly through elbow 194 that is normally kept closed by a plug 195 when the auger is not in use, Figs. l and 2. The auger rotor 127 is always rotated in the same direction and that direction being so as to give right hand rotation to the auger 25. On the gear case 39 at one side thereof is a gear case filler plug 196 and on the opposite side thereof is a gear case oil level plug 197, Fig. 2.

The gear case 39 and the assembly of the internal gears 151, 162 and spacers 152 and 161 are held tixed against axial displacement upon the valve and motor housing 38 by long gear case, cap screws 198, Figs. 3a and 6. The internal gears 151 and 162 are notched on their peripheries as indicated at 199, Fig. 6, to receive portions of the cap screws 198 and thereby be held against rotational displacement in the gear case.

The air hose d4 is connected to an elbow 200 that is screw tted upon an air inlet swivel 201 having a tapered portion 202 fitted in an air inlet swivel nut 203, Fig. 2. 1n a transverse hole 204 is a throttle valve bushing 205 which contains an auger motor throttle valve 206 which is normally held in the orf position by a throttle valve return spring 207 anchored at one end to the bushing 2115 as indicated at 268 and at the throttle valve as indicated at 259, Fig. 2. The throttle valve has a reduced portion 210 which extends through a boss 211 on the housing 38 and to which an auger motor valve handle 212 is keyed asl indicated at 213. This handle 213 is held against axial displacement by a nut 214. The throttle valve 206 has a central opening 215 and a side port 216 (Fig. 3b) by which the air will be delivered to a port 217 in bushing 205 and passage for delivery to the auger motor 12d. The handle 212 is turned down `to cause the air to flow to the auger motor 124 and upon release of the handle it will automatically be turned back by the spring Z117 to the normally closed position whereby the operator can easily stop the rotation of the auger by simply releasing the handle.

A stop bolt 218 extends downwardly through a boss 219, Pig. 3b, on the top of the housing 36 and into an arcuate groove 220 in the throttle valve 206 whereby to limit the turning movement of the throttle valve 205 to an angle of ninety degrees.

In the bushing 265 is a side hole 221, Fig. 2, by which compressed air is delivered to a passage 222 for delivery to a feed motor throttle valve bushing 223 in a transverse opening 224 in the valve housing 38 rearwardly of the auger motor throttle valve 206. Within the bushing 223 is a feed motor throttle valve 225 shouldered at one end against the end of the bushing 223 as indicated at 226 and held within the transverse opening 224 by a threaded throttle valve cap 227 through which a shank 228 of the valve 225 extends. On the shank 228 there is keyed a handle 229 by a key 2341. A nut 231 holds the handle 229 in place on the shank 228. A stop bolt 232 extends downwardly through a boss 233 and into an arcuate stop recess 234 in the valve 225. The throttle valve 225 has an annular recess 235 which registers at all times with a hole 236 in the bushing 223 to receive compressed air from the passage 222.

with the valve 225 then in the neutral position, as shown in Figs. 2, 3b and 9, the compressed air within the annular groove 235 is held against movement through the valve 225. Upon the valve 225 being turned by its handle 229 in an elevated position, so that one end of the arcuate slot 234 bears against the stop pin 232 projecting thereinto, a side slot 237 communicating with the side of the groove 235 will direct air under pressure through the port 115, Figs. 3b and 9, to cause the air to be delivered through space 113 and ports 114 whereby to drive the feed motor rotor 96 in a clockwise direction as viewed in Fig. 9. The air from the feed motor will exhaust to the atmosphere through slots 119 and hole 120 into the guide shell 36. Any pressure that has built up on the opposite side of the feed motor rotor will exhaust through ports 117, space 116, passage 118, hole 118', in bushing 223 and through a side hole 238 in the valve 225, longitudinally aligned with the side slot 237, a valve central hole 239 transverse opening 224 and small ports 240 to the atmosphere.

If the valve 225 is pushed down from the neutral position, shown in Fig. 3b, so that the opposite end of the arcuate stop slot 234 comes to rest against the pin 232 a side slot 241 communicating with the groove 235 will receive air under pressure so as to deliver this air through the hole 118' in the bushing 223, passage 118, space 116, ports 117 of the feed motor liner 94 to drive the rotor 96 in the reverse direction and effect the return of the auger unit to its retracted position. This air is exhausted through the slots 119 and hole 120 to the atmosphere. Any pressure that is built up at the opposite side of the rotor will be delivered from space 113 through hole 115, hole 115 in the bushing 223, a side hole 242 in the valve 22S, central hole 239 in the valve 225 and exhaust ports 240 to the atmosphere.

In order to hold the valve in either of its positions, teeth 243 are provided on the underside of the shoulder 226 and are to be engaged by a spring biased detent pin 244 that is held in place by a spring. 245 and plug 246. The detent plunger 244 has a flat face 247 thereon that is engaged by a pin 248 within a hole in the housing adjacent to the plunger 244 so as to engage with the flat face 247 of the plunger and thereby hold the plunger 244 against rotation upon the teeth 243 on the valve 225.

The bottom 43 of the guide shell 3e is held in a slidingcone device 26, Fig. 8, by a clamp plate 251 engag ing with one side of the bottom 48 and a fixed hook portion 252 engaging the opposite side of the bottom 4S. A clamp bolt 253 having head 253' extends through the cone and on this bolt is attached a nut 254 that is tightened on the clamping bolt 253 and against the clamp plate 251. The cone 26 is fitted in a saddle clamp 27 and held by similar clamping means thereupon. The saddle clamp is fixed to the post support 28 in the usual manner.

Air is delivered to the valve and motor housing 38 at a pressure of eighty pounds per square inch. The feed motor is operated at approximately four thousand revolutions per minute and through the gear reduction connected between the feed motor and the feed nut, the feed nut is driven at approximately one thousand revolutions per minute. The auger motor is driven at three thousand revolutions per minute. The planetary gearing in the gear case 39 reduces the output speed of the auger chuck so that the auger element is driven at tive hundred revolutions per minute.

It should now be apparent that there has now been provided an air driven rotary earth auger comprising an auger unit that is powered to move along a guide shell through its feed nut operating on a normally stationary feed screw rotatably secured between its opposite ends of the guide shell and with one end having engagement with an overload clutch device which will release upon the feed nut being caused to bind upon the feed screw. Buffer springs are disposed at the opposite ends of tie guide shell to receive the auger unit at the end of either the forward stroke or upon the retracting stroke.

It should also be apparent that by this arrangement the feed motor is provided in the same housing with the auger motor and operated by a single air pressure source leading to the housing and controlled by valves disposed in the auger unit and in the same housing with the feed and auger drive motors.

While various changes may be made in the detail construction of this air driven rotary earth auger, it shall be understood that such changes shall be within the spirit and scope of the present invention as defined by the appended claims.

What is claimed is:

l. In a rotary earth auger, a guided shell, a feed screw journalled at the opposite ends of said guide shell and extending longitudinally therethrough, overload release means on said guide shell and engageable with said feed screw to normally retain the same against rotation on said shell, a rotary auger unit having a power driven feed nut extending into said shell and operable along said feed screw whereby the auger unit may be fed along said guide shell, said feed screw thereby releasable through the overload release means upon said feed nut binding upon the feed screw, said feed screw having a splined end portion, said overload release means including a clutch sleeve surrounding the splined end portion of the feed screw, an internal cone member splined upon said end portion of the feed screw, a clutch housing fixed to the end of said guide shell, said clutch sleeve fixed to said housing, a clutch spring disposed in said clutch housing and reacting between said clutch 4cone and the housing to normally retain said cone in clutch engagement with said clutch sleeve, said feed screw having a ange, a buffer spring surrounding the feed screw shaft and having an enlarged end, a bracket for mounting said clutch housing and recessed to receive said enlarged end of the buffer spring and the ange of the feed screw whereby to retain the buffer spring and the feed screw against axial displacement relative to said guide shell.

2. 1n a rotary earth auger, an elongated guide shell, a feed screw extending through the guide shell and having its respective ends connected to the opposite ends of the guide shell, means for holding the feed screw within the guide shell against rotation, a rotary auger unit including feed and auger motors mounted therein, a feed nut operable upon said feed screw and carried by said auger unit, drive means connecting said feed nut to said feed motor including an idler gear, uid control means on said unit for selectively controlling the operation of said feed and auger motors, planetary reduction gear means drivingly connected to said auger motor and having a chuck extending therefrom and adapted to receive an auger element, and said auger unit further having a valve and motor housing having a portion depending into said guide shell to rotatably support a feed nut, a rear end plate secured to an open end of said housing and having a portion depending into the guide shell to rotatably support the feed nut, a hollow stud carried on said end plate, a lubricant fitting carried on the end of said stud and accessible from the exterior of said end plate, said stud having radial holes to permit lubricant to be passed to the idler gear and said idler gear having openings to permit the ow of lubricant to said feed nut, said housing and end plate depending portions having lubricant passages for the delivery of lubricant to the feed nut.

3. A rotary earth auger, as defined in claim 2, and means for providing lubricating uid within the space between the rear end of said housing and said end plate and about the idler gear, said lubricating means including passages in said idler gear and in said housing and end plate for delivery to said feed nut, said housing having a cylindrical opening and said feed motor fitting said cylindrical opening and sealing off space forwardly of the feed motor from space surrounding said gears and a vent pin extending through the feed motor and engaging with said housing to hold the feed motor against rotation in said cylindrical opening and said vent pin equalizing the pressure between the space forwardly of the feed motor and the space rearwardly thereof whereby leakage of air accumulating in the space forwardly of the feed motor is directed to the space rearwardly of the motor to provide pressure for normally urging the How of lubricant over said gears and toward said feed nut.

4. A rotary earth auger, as defined in claim 3, and a cylindrical spacing member disposed in the cylindrical opening and abutting the rear end of the feed motor, said spacing member receiving and supporting said stud and said rear end plate abutting and retaining said spacing member within the cylindrical opening, said spacing member having passage means for receiving said vent pin whereby said space member will be held against rotation relative to said feed motor and will communicate the air passing rearwardly through the vent pin to the space at the rear of the feed motor.

5. An air driven rotary earth auger comprising a guide shell, a feed screw connected between the ends of said guide shell means, an auger unit comprising a valve and motor housing, a rear end plate including a portion of an integrally formed gear case, said valve and motor housing having `a depending portion and said end plate having a corresponding depending portion, a feed nut operable upon said feed screw and retained between depending portions of said housing and rear end plate, an air driven feed motor secured within said housing and gear means extending between said feed motor and the feed nut to drive the same, and an air driven auger motor xed within said housing and having a forwardly extending pinion gear, a planetary gear spider journalled upon said auger motor pinion gear and a chuck spindle spider having a planetary gear thereon and journalled upon said rst mentioned spider to be driven by the same, internal gears against which the respective planetary gears may react, said gear case being connected to the valve and motor housing and retaining said planetary gearing therewith, and valve control means disposed on said valve and motor housing for controlling the ffow of air to said respective feed and auger motors.

6. A rotary earth auger, as defined in claim 5, and spacing members separating said internal ring gears from said auger motor and from each other, each of said ring gears having notches on the periphery thereof `and through bolts extending tln'ough the gear case and aligned With the notches of said internal gears and into said valve and motor housing whereby to retain said internal gears against rotation within the gear case and the gear case upon said valve and the motor housing.

7. A rotary earth auger, as defined in claim 5, and bearing assemblies retaining said spindle for rotation upon said gear case, a lock nut on said spindle retaining said spindle against rotation between said ball bearing assemblies, a cap having sealing means disposed over said lock nut and secured to the end of said gear case, a chuck fixed to said chuck spindle spider and adapted to receive an auger element.

8. ln a rotary earth auger of the character described, a guide shell, la rotatable feed screw journalled at the opposite ends of said guide shell and extending longitudinally therethrough, overload release means at one end of the guide shell engaging a corresponding end of the feed screw to restrain the latter from rotating, a rotary auger unit having a power driven feed nut extending into said shell and operable along said feed screw whereby the auger unit may be fed along said guide shell, said feed screw thereby being releasable for rotation through the overload release means upon said feed nut binding upon the feed screw, whereby the feed screw is ineffective while released to cooperate with the driven feed nut to effect operation of the feed nut along the feed screw, said feed screw having a straight splined end portion, said overload release means including a clutch sleeve surrounding the splined end portion of the feed screw, an internal cone member slidably splined upon said end portion of the feed screw, a clutch housing fixed to the end of said guide shell, said clutch sleeve fixed to said housing, a clutch spring disposed in said clutch housing and reacting between said clutch cone and the housing to normally retain said cone in clutch engagement with said clutch sleeve.

References Cited in the file of this patent UNITED STATES PATENTS 1,516,858 Kingsbury Nov. 25, 1924 1,818,393 Hansen Aug. 1l, 1931 2,221,118 Smith et al Nov. l2, 1940 2,316,192 Sinclair Apr. 13, 1943 2,365,687 Curtis Dec. 26, 1944 2,407,613 Mann et al. Sept. 10, 1946 2,525,422 Nast Oct. 10, 1950 

